Here's Why Climate Change Can Make Seasonal Allergies Even Worse

AYLIN WOODWARD, BUSINESS INSIDER

23 MAY 2019

Spring brings fresh blooms and warmer weather, but those seasonal changes also herald the start of allergy season for about 40 million Americans. As pollen proliferates, so too does the sneezing, itching, and nose blowing that comes with hay fever.

If it feels like your allergies keep getting worse with each trip around the sun, that might really be the case. And there's a major culprit to blame: climate change.

According to the Union of Concerned Scientists, carbon dioxide (one of the greenhouse gases human activity emits that traps heat on the planet) increases plant growth rate. That, in turn, increases the quantity and potency of pollen.

Isabella Annesi-Maesano, research director at the French Institute of Health and Medical Research, told Business Insider that this warming is the reason we're seeing an "earlier onset of pollen season" as well.

A recent study published in The Lancet analysed the length of pollen season and the amount of pollen per plant in 17 locations across the Northern Hemisphere.

According to the data, which was collected over 26 year, 70 percent of the locations saw increases in the total amount of circulating pollen per growing season. In 65 percent of the spots, the pollen season got longer due to an "ongoing increase in temperature extremes," the authors reported.

Lewis Ziska, the lead author of that study, works as a weed ecologist with the US Department of Agriculture. He told the Union of Concerned Scientists about another climate-related allergy problem: Plants use carbon dioxide to make food via photosynthesis, but extra carbon dioxide in the air leads pollen-spreading, allergy-inducing weeds to grow faster than "useful plants" like rice and wheat.

Ragweed is the primary trigger of fall hay fever, according to the AAFA. Warmer temperatures give ragweed longer growing seasons, enabling the plant to continue producing more pollen later into the fall.

If carbon-dioxide emissions continue unchecked, ragweed pollen production could increase by 60 percent to 100 percent in the next 65 years. Ragweed pollen could also become more allergenic as carbon-dioxide levels increase, according to the AAFA.

Allergies might continue to get worse

According to Annesi-Maesano, flooding due to sea-level rise can also provoke another kind of allergy.